It's not dumb, all mayor central banks of the planet have printed 50% of GDP on their currencies including the dollar to deal with the pandemic. That means that you risk losing 50% of the value of your cash, so you invest it and you diversify to protect yourself, but because everybody with money is doing exactly that, you have massive asset bubbles that also risk your money, so its hard to find something to invest in.

Elon took a relative small bet by been the first mayor company to buy massive amounts of crypto and so far he has made bank. Only the future will tell if it was a good move in the long run.